The enormous variety of biochemical reactions that comprise life are nearly all mediated by a series of biological catalysts known as enzymes. Enzymes are proteins which possess specific catalytic activities that enable them to catalyze a series of reactions, hence enabling metabolic pathways to degrade and to reconstruct products needed to maintain organisms. By the binding of substrates through geometrically and physically complementary reactions, enzymes are stereospecific in binding substrates as well as in catalyzing reactions. The stringency for this stereospecificity varies as some enzymes are more specific to the identity of their substrates, while others are capable of binding multiple substrates and can catalyze numerous types of reactions.
Examples of enzymes include, for example, arginine methyltransferases, glycosyltransferases, gamma-glutamyltraspeptidases, phosphoribosylglycinamide transferases, acyltransferases, acyl-CoA dehydrogenases, fatty acid amide hydrolases, aminotransferases, zinc carboxypeptidases, protein kinases, DEAD helicases, short-chain dehydrogenase/reductases and phosphatases. Such enzymes have the ability, for example: 1) to transfer an activated sugar residue to an acceptor molecule; 2) to modulate the processing, folding, and secretion of proteins; 3) to transport amino acids in the form of their gamma-glutamyl derivatives; 4) to regulate the metabolism of glutathione; 5) to regulate the synthesis of purines; 6) to modulate cell division and proliferation; 7) to modulate cell death; 8) to transfer an acyl chain to a lipid precursor; 9) to regulate lipid biosynthesis; 10) to catalyze the transfer of hydrogen and electrons from one compound to another; 11) to catalyze the I,-dehydrogenation of fatty acyl-CoA derivatives; 12) to bind and catabolize fatty acid amides; 13) to modulate metabolism, e.g., amino acid metabolism; 14) to bind an amino acid, e.g., L-alanine; 15) to bind an oxo acid, e.g., pyruvate; 16) to modulate the formation of a zinc ion complex with a carbonyl group of a substrate polypeptide and polarization of the carbon-oxygen bond; 17) to modulate formation of a tetrahedral intermediate due to attack of the carbonyl carbon by water in a reaction assisted by a carboxylate side chain of glutamate; 18) to modulate the production of a dianion intermediate by rapid ionization of the tetrahedral intermediate produced; 19) to modulate ATP dependent nucleic acid unwinding; 20) to modulate RNA metabolism (e.g., nuclear transcription, and mRNA splicing); 21) to modulate steroid biosynthesis or metabolism (breakdown); 22) to catalyze the removal of a phosphate group attached to a tyrosine residue in a protein; 23) to catalyze the removal of a phosphate group attached to a serine or threonine residue in a protein; 24) to modulate an intracellular signaling pathway, e.g., a MAP kinase or ERK kinase pathway; 25) to regulate the transmission of signals from cellular receptors, e.g., cardiac cell growth factor receptors; as well as many others. Accordingly, there exists a need to identify additional human enzymes, for example, for use as disease markers and as targets for identifying various therapeutic modulators.